Effect of carbapenems on the Pseudomonas aeruginosa fitness and virulence.. Long exposure to sub-inhibitory concentration of carbapenems and its effect on the Pseudomonas aeruginosa fitness and virulence

Pseudomonas aeruginosa is one of the most relevant oportunistic human pathogens. This bacterium has an extraordinary capacity for developing resistance to most of the available antipseudomonal antibiotics, including carbapenems, through the selection of mutations in various chromosomal genes such as oprD, ampC or several efflux systems. Previous studies have shown that there is a number of genes related to central metabolic functions which also play a role in antimicrobial resistance. The aim of this study is to characterize the evolution of antibiotic resistance to carbapenems upon exposure to sub-inhibitory concentrations of such antimicrobial agents, as well as the fitness consequences and changes in virulence traits for the bacterium by comparing wild type populations with their derivative developed strains exposed to growing concentrations of imipenem during approximately 150 generations. Complete genome was carried out in order to gain a deeper understanding of the evolution of resistance to carbapenems in wild type susceptible strains and its impact on the fitness and virulence of P. aeruginosa.